Air and water conveyor/cooler for hot loose materials

ABSTRACT

The present invention regards a conveyor/cooler for hot loose materials produced by boilers and various industrial processes, mainly comprising a sealed metal container ( 1 ) connected to a boiler ( 2 ) or to an incinerator from which, thanks to the gravitational effect, the material ( 3 ) that leaves the combustion chamber falls. Inside of said container ( 1 ) a metal conveyor belt ( 4 ) is placed whereon the hot loose material ( 3 ) to be cooled is placed. The cooling of the material ( 3 ) occurs through the feeding of an air flow picked up from the outside environment integrated with atomized water sprinkled on the hot material ( 3 ) through a system of injecting nozzles ( 5 ) installed inside of the metal container ( 1 ).

The present invention is about an air and water conveyor/cooler for hotloose materials such as either heavy ashes generated by boilers, orashes and slags produced in the various industrial processes likeburning, baking, etc.

The innovative features, the objects and the advantages of the presentinvention will be understood in a not limiting way from the followingdescription and from the annexed drawings relative to some embodimentswherein the different figures show:

FIG. 1 is a lateral diagrammatic view of a conveying/cooling deviceaccording to the present invention for hot loose materials (3) comingfrom vacuum operated combustion chambers (2);

FIG. 2 is a lateral diagrammatic view of a conveying/cooling deviceaccording to the present invention for hot loose materials (3) comingfrom pressure operated combustion chambers (7);

FIG. 3 is a lateral diagrammatic view of a conveying/cooling deviceaccording to the present invention having the belt equipped with slots;

FIG. 4 is a plan diagrammatic view of a conveying/cooling device of hotloose materials (3) according to the present invention;

FIG. 5 is a diagrammatic view of the plano-volumetric arrangement of thenozzles (5) of the water sprinkling system in the small side panels (16)of the metal container (1);

FIG. 6 is a diagrammatic view of the plano-volumetric arrangement of thenozzles (5) of the water sprinkling system in the upper cover of themetal container (1);

FIG. 7 is a diagrammatic view of the weighing system (8) installed onthe conveyor belt (4) for the capacity control;

FIG. 8 is a diagrammatic detail of the strap iron (15) installed on themetal container (1) for the capacity control; and

FIG. 9 is a diagrammatic view of the metal conveyor belt (4) having theplates equipped with slots (6).

It must be clarified on this matter that the same reference numbers inthe various figures indicate similar or matching parts.

The conveyor/cooler according to the present invention uses for thetransport of the hot loose materials (3), specifically such as heavyashes and other combustion byproducts coming from the boilers orincinerators (2-7), a driving means with a steel metal belt (4) insertedin a sealed metal container (1).

The hot loose material (3) thanks to the gravitational effect leaves theboiler or incinerator (2-7) under which the metal conveyor belt (4) isfound, whereon the material (3) is laid down by forming a continuous bedtraveling towards the unloading area (9).

The dusty material with a smaller grain size which falls from the metalbelt (4) and is laid down on the bottom of the container (1) is conveyedtowards the outlet (9) through the use of a scraping conveying means(10) with chains or with a metal net.

The speed of the conveyor belt (4) can be adjusted with respect to thecapacity of the conveyed material (3) and of the specific cooling needs,so as to optimize the distribution of the ashes on the belt in order toincrease the thermal exchange surface.

The cooling of the loose material (3) exiting from the combustionchambers at temperatures close to 800/900° C., takes place through thejoint feeding of air flows and water jets atomized inside of thecontainer (1).

The external air is took back in the metal container (1) through the airintakes by using the vacuum found in the combustion chamber when theconveying/cooling system is connected to vacuum operated boilers (2). Inthe event that the conveying/cooling system were to be installeddownstream of the boilers or incinerators wherein the combustion occursunder pressure (7), the cooling air is induced inside of the metalcontainer (1) with the aid of a forced ventilation system.

The air flow enters from the air intakes (12) and passes through themetal container (1) by heading against the stream with respect to theadvancing of the hot material (3) conveyed by the metal belt (4) towardsthe unloading area (9).

In order to improve the efficiency of the cooling process, the metalplates of the conveyor belt (4) can be equipped with slots (6) throughwhich the cooling air can reach the bottom of the traveling continuousbed and can flow inside the layer of the material (3). In such manner,in the metal container (1) additional air intakes (11) are provided,whose placement is such to generate a further cooling flow, differentfrom the previous one.

Regarding the second air flow sucked by the intakes (11), a part of itflows at the bottom of the container (1) underneath the conveyor belt(4) towards the unloading area (9) where is mixed to the first flowcoming from the air intakes (12), while the remaining part flows throughthe slots (6) made in the metal plates of the conveyor belt (4). Bytaking advantage of the difference in pressure existing between theupper section of the conveyor belt and the lower one, the air passesthrough the whole thickness of the traveling continuous bed of hotmaterial (3), by cooling its bottom and the inner layer.

The geometry, the number and the arrangement of the slots (6) made inthe plates of the conveyor belt (4) are defined as a function of thechemical-physical features of the conveyed material (3) and of thedesired cooling degree, so as to avoid a possible leakage.

The fraction of used air for the two cooling portions of the incomingflow from the intake valves (11) can be measured through an adjustmentmechanism (13) placed in the lower part of the metal container (1) inproximity of the unloading area (9).

The capacity of the cooling air is a function of the air intakes (11-12)and of the pressure difference established in the metal container (1),and it can be measured out by acting on the adjustment members of theintake valves.

The air absorbs the heat that the hot material (3) gives up thanks tothe convective thermal exchange that the air directly has with the samematerial, with the walls of the metal container (1) which areradiatively heated, with the metal belt (4), both in its forward run andits return run, and at last through the possible post-combustion of theunburnt matter found in the conveyed material (3). It is convenient toclarify that in the specific case the metal conveyor belt (4) operatesas a regenerative heat exchanger, by absorbing the heat from the hotloose material (3) in the forward run and by giving it up to the coolingair during the return run.

When the conveyor/cooler is applied to the boilers or vacuum operatedincinerators (2), the air thus heated is taken back in the combustionchamber where is mixed with the main combustion air, by recovering insuch manner part of the thermal energy accumulated during the coolingphase of the hot material (3). When instead the system is applied topressure operated combustion chambers (7) the air is directly ejectedinto the atmosphere, after an appropriate filtering for the recovery ofthe volatile substances.

In order to further reduce the temperature of the hot material (3)conveyed by the metal belt (4) the air cooling system is integrated withthe water cooling system.

The water cooling system is made of a determined number of nozzles (5)which can be activated when the air only cooling capacity is not enoughto guarantee the desired thermal reduction. The nozzles (5) are arrangedin such manner that the atomized water jets would be directed on theupper part of the hot loose material (3) conveyed by the metal belt (4)during the forward run towards the unloading area (9).

The integration of the atomized water sprinkling system allowsincreasing the thermal exchange with the conveyed material (3),therefore it is possible to reduce the horizontal dimensions of themetal container (1) compared to the cooling carried out with air only.

The sprinkling system can also be used in the applications wherein theobject is not just that of reducing the temperature of the conveyedmaterial (3), but it is also that of achieving a preset moisturizing ofthe same material.

The number of nozzles (5) therein, their plano-volumetric arrangementinside of the metal container (1) and the kind of each single nozzle (5)are predefined according to the chemical-physical characteristics of theconveyed material (3), according to the capacity of the same materialand according to the desired cooling degree.

The sprinkling system can be connected to the compressed air network soas to jointly atomize water and air with respect to the need to optimizethe cooling by appropriately measuring out the capacity of the twoelements.

The capacity of the nozzles (5), the intervention sequence and theduration of the activation are defined according to the temperature ofthe material (3) and according to the level of the capacity of the samematerial, through the on-line processing of the signals received by thetemperature sensors (14) installed inside the metal container (1), andby the value of the capacity of the material (3).

The instant value of the capacity of the hot loose conveyed material (3)can be measured by either utilizing a weighing system (8) directlyconnected to the conveyor belt (4), or by using a strap iron (15) hingedto the upper cover of the metal container (1) suitable to detect theheight of the layer of the conveyed material (3).

It is obvious that several modifications, adjustments, additions,variations and substitutions of the elements with others which arefunctionally equivalent can be made to the embodiments of the inventiondescribed in an explanatory but not limiting way without falling out ofthe scope of protection recited by the following claims.

1. A conveyor/cooler of solid hot loose materials (3) generated byboilers and by various industrial processes, comprising a sealed metalcontainer (1) connected to combustion chamber of a boiler or anincinerator (2, 7), and a metal conveyor belt (4) in the metal container(1) for receiving the hot loose material (3) from the combustion chamberby gravity and forming a traveling continuous bed of material cooled bythe joint action of atomized water jets and air flows, and whereinnozzles (5) are provided in the metal container (1) and define anatomized water sprinkling system and are connected to a compressed airplant in order to jointly atomize water and air with respect to the needto optimize the cooling by appropriately measuring out the capacities ofthe water and air.
 2. The conveyor/cooler according to claim 1,characterized in that the conveyor belt (4) includes a regenerative heatexchanger which absorbs the heat from the material (3) during traveltoward an unloading area (9) and it gives it up to the air in the returnrun.
 3. The conveyor/cooler according to claim 1, characterized in thatthe device is adapted for installation underneath the boilers orincinerators wherein the combustion occurs either under vacuum (2) orpressure (7) with respect to the outer atmosphere.
 4. Theconveyor/cooler according to claim 3, characterized in that the deviceallows the recovery of thermal energy taken from the hot material (3)when it operates under vacuum; said recovery takes place by introducingthe heated air with the heat given up by the material (3) into thecombustion chamber of the boiler (2) by thus mixing it to the maincombustion air.
 5. The conveyor/cooler according to claim 1,characterized in that the intake air capacity into the metal container(1) from air intake ports (11, 12) can be adjusted in order to optimizethe cooling.
 6. The conveyor/cooler according to claim 1, characterizedin that a scraping conveyor (10) with chains or with a metal net isprovided in order to scrape the material's dust from the bottom of thecontainer (1), wherein is deposited and is conveyed towards an unloadingarea (9).
 7. The conveyor/cooler according to claim 1, characterized inthat the number of nozzles (5) therein, their plano-volumetricarrangement inside of the metal container (1) and the type of eachsingle nozzle (5), are preset according to the chemical-physicalcharacteristics of the conveyed material (3), according to the capacityof the same material and according to the desired cooling degree.
 8. Theconveyor/cooler according to claim 1, characterized in that the capacityof the nozzles (5), the intervention sequence and the duration of theactivation are defined according to the temperature of the material (3)and according to the level of the capacity of the same material.
 9. Theconveyor/cooler according to claim 8, characterized in that inside themetal container (1) temperature sensors (14) are installed whose signalsare used in order to adjust the operation of the atomized watersprinkling system.
 10. The conveyor/cooler according to claim 7,characterized in that the spraying angle of the nozzles (5) covers theentire surface of the traveling bed formed by the hot material (3). 11.The conveyor/cooler according to claim 1, characterized in that theplates of the metal conveyor belt (4) are equipped with appropriateslots (6) that allow the passage of the cooling air flow through thewhole layer of the continuous bed formed by the hot loose material (3)traveling on said metal belt (4).
 12. The conveyor/cooler according toclaim 11, characterized in that the geometry, the number and thearrangement of the slots (6) made in the plates of the metal conveyorbelt (4) is defined as a function of the type, the amount and mainlywith respect to the grain size of the conveyed material (3) so as toprevent this material from leaking and falling to the bottom of themetal container (1).
 13. The conveyor/cooler according to claim 11,characterized in that the fraction of cooling air flow which runsthrough the slots (6) in the plates of the metal belt (4) is adjustable,with respect to the specific cooling needs and to the possible presenceof unburnt matter.
 14. A conveyor/cooler of solid hot loose materials(3) generated by boilers and by various industrial processes, comprisinga sealed metal container (1) connected to combustion chamber of a boileror an incinerator (2, 7), and a metal conveyor belt (4) in the metalcontainer (1) for receiving the hot loose material (3) from thecombustion chamber by gravity and forming a traveling continuous bed ofmaterial cooled by the joint action of atomized water jets and airflows, and equipped with a capacity control system for the hot loosematerial (3) conveyed by the metal belt (4) which allows determiningreference values suitable to adjust the intensity of the water and airflows.
 15. The conveyor/cooler according to claim 14, characterized inthat the capacity control of the hot loose conveyed material (3) iscarried out by using a weighing system (8) directly connected to theconveyor belt (4).
 16. The conveyor/cooler according to claim 14,characterized in that the capacity control of the hot loose conveyedmaterial (3) can be carried out by using a strap iron (15) hinged to thecover of the metal container (1).